In the past, a number of devices or machines have been constructed for rotating or tumbling stones, minerals and other rough irregular objects in the presence of an abrasive compound and substance, which action, when continued over extended periods of time, completely removes all irregularities and imparts a high finish to the material being processed. One of the disadvantages in the previous devices have been the length of time required in order to finish and polish a load, since it is obvious that hard materials such as gem stones and minerals require long periods of tumbling action in the presence of abrasives to accomplish this desired result. Furthermore, many of the previous devices have not thoroughly mixed and agitated the load with the result that certain parts of the load or charge are polished at the end of a treatment period, whereas other parts of the load or charge which have not received the full agitating or vibrating effect are not in satisfactory condition and polishing treatments must be continued.
Illustrative of the prior devices is that described in U.S. Pat. No. 3,197,922 issued to Edward Earl Smith, Aug. 3, 1965. The Smith device is an expensive, rather complicated device which depends on a drum supported on a platform which is spring loaded to a base. The length of the lever arm between the center of the drum and each of the springs must be precisely set and be uneven in order to provide an oscillating or tumbling motion to the motor charge within the drum. A complicated pulley and crank shaft device is utilized to provide the rotating and oscillating movement.
It has been found that the polishing and finishing time, when using the device according to the present invention, is reduced marketly from a period of weeks to continuous polishing required in previous devices down to a matter of hours or a few days in the case of the present invention, and particularly, the present invention is an improvement over the Smith device.